> The property_accessor service is only going to be defined for Symfony 2.2

Of course, how could I forget.

> Perhaps as a fallback, we can use the static factory method in PropertyAccess?

Or we don't use `property_accessor` at all and simply call `PropertyAccess::getPropertyAccessor();` were we need it. The PropertyAccess has no dependencies and it will make the code even more cleaner than before.